It was once quite common for some trades (e.g. carpenters, joiners, cabinetmakers, etc) to make their own boxes in order to store more expensive and less used tools, especially those with additional cutters, fences, etc. I have a number of more specialist planes (mainly router planes and shoulder planes) which came in home-made wooden boxes, presumably made by the owners to replace the cheap, low quality pasteboard boxes originally supplied by the manufacturers. So, it may or may not be an apprentice piece, but either way such boxes aren't uncommon and they can often end up being pressed into service for other purposes.
BTW apprentice pieces were generally made using a variety of "show" techniques such as dovetail joints, etc as they were essentially meant to show the skill level achieved. For example, I made a tool box with half-lapped dovetail joints, a piano hinge and a fitted interior with cleats to hold various tools. That box was made as a closed item and the opening side (basically 2/3 of one side) had to be hand sawn after the box was made. The real apprentice piece for me was a 1/3 scale oak part staircase complete with a kite winder - so not a tool box
